In case you missed it, the last 12 months (May ’18 through Apr ’19) is the wettest 12-month stretch on record for the US. A warmer world turns up the hydrology dial. When we are sent the bill for climate change, it comes in the context of our water.
I will explain what he is talking about shortly, but I want to deal with the “meteorology” of why this period has been so wet. I have to do that because someone is eye-rolling right now and saying “but the climate changes naturally, Dr. Shepherd” or “we’ve always had heavy rain.” My quick response is that your lawn grass grows naturally too, but it grows differently when the soil is fertilized. I will visit this topic later with a more robust discussion.
The graphic above shows how wet much of the country has been in the 344 climate divisions of the continental U.S. Parts of the mid-Atlantic and the upper Midwest were “record-breaking” wet. By the way, I suspect someone in Washington State is thinking “but where I live has been drier than normal.” Based on the data, that statement is true but says nothing about the rest of the U.S. or climate change, but I digress. Jason Samenow wrote an excellent commentary in the Washington Post Capital Weather Gang on “why” that region has been so wet. I will summarize his key “meteorological points”:
- A persistent high pressure system has funneled moisture from the Atlantic Ocean and Gulf of Mexico into much of the eastern U.S.
- A second area of high pressure near Alaska influenced the jet stream pattern.
- The jet stream, which strongly governs where mid-latitude systems and fronts, has aimed storm tracks right into the Upper Midwest and Mid-Atlantic.
Other factors include Hurricane Florence and the weak El Nino that recently began, but much of the record-breaking period was associated with El Nino neutral or very weak condition. In fact, the NOAA NCEI synoptic overview for January 2019 stated, “The Earth’s ocean-atmosphere system continued in an ENSO-neutral state during January 2019….” I am on the fence on the El Nino connection, but experts like SUNY-Albany atmospheric scientist Paul Roundy argue that there may be more of signal than we think. As Samenow pointed, “chance” and weather pattern variability certainly could explain the last 12 months. However, it is irresponsible to ignore climate change because events are consistent with the expected physics.
Deke Arndt’s Tweet tapped into something climate scientist predicted many decades ago, an accelerating water cycle. NASA’s Earth Observatory provides a clear summary of what an accelerated water cycle means:
as the lower atmosphere becomes warmer, evaporation rates will increase, resulting in an increase in the amount of moisture circulating throughout the troposphere (lower atmosphere). An observed consequence of higher water vapor concentrations is the increased frequency of intense precipitation events, mainly over land areas.
Is this happening? The answer is yes. The 2018 U.S. National Climate Assessment report shows that the heaviest precipitation events have become more intense since the late 1950s (graphic above). Climate models also suggest that this trend will continue. A growing body of research continues to show that the warming Arctic affects the jet stream through a process called Arctic Amplification. According to NOAA’s website:
Scientists have observed that the reduced temperature difference between the North Pole and tropics is associated with slower west-to-east jet stream movement and a greater north-south dip in its path. This pattern causes storms to stall and intensify, rather than move away as they normally used to do. At midlatitudes, more extreme weather results from this new pattern, including droughts, floods, colds spells, and heat waves.
Attribution studies are becoming more skilled at linking contemporary extreme weather events to climate change. It is one of the new frontiers of climate science. Arndt, one of the best climate communicators I know, has an excellent way to explain attribution. His Tweet thread on May 10th nails it:
A way to think about the relationship between changing climate and Big Weather. Consider parent/child, teacher/student, coach/athlete, mentor/apprentice relationships. The parent (climate) rarely dictates day to day actions, but is hugely influential in long-term outcomes….Change the climate, and the things that dictate “extreme behavior” are largely the same, but those ingredients are coming together in different ways. In other words, the drivers of his day-to-day behaviors are largely the same, but the trajectory of his life have changed.
As a I close, it is important to understand this point. Flooding often takes a backseat to more telegenic and violent weather hazards like tornadoes or hurricanes. National Weather Service data continues to show year after year that flooding is the 2nd deadliest weather hazard behind heat. It is usually ranks near the top in cost also. Flooding is not just a function of what falls from the sky though. Paved surfaces, dams, and outdated stormwater engineering are also in the equation, which means there is unequivocally some type of anthropogenic effect on flooding.
< div _ ngcontent-c14 ="" innerhtml ="(* )I am constantly cautious when composing this kind of short article since some contrarian is being in his basement all set to catch negligent declarations like "The U.S. had its ____ est year" ever The error that some make is utilizing “ever.” Just recently, climatologists exposed that the U.S. experienced its wettest 12- month stretch on record S ince official environment records have actually been kept (1895 to 2019 in this case), the duration from Might 2018 to April 2019 got more rainfall than any other duration of the very same period. Here is the clinical context behind why it took place, and yes, environment modification belongs of the conversation.
In case you missed it, the last12 months( Might’18 through Apr’19) is the wettest12- month stretch on record for the United States. A warmer world shows up the hydrology dial. When we are sent out the expense for environment modification, it is available in the context of our water.
I will describe what he
is speaking about soon, however I wish to handle the” meteorology “of why this duration has actually been so damp. I need to do that since somebody is eye-rolling today and stating” however the environment modifications naturally, Dr. Shepherd “or” we have actually constantly had heavy rain.” My fast reaction is that your yard turf grows naturally too, however it grows in a different way when the soil is fertilized. I will visit this subject later on with a more robust conversation.(**** )
The graphic above demonstrate how damp much of the nation has actually remained in the(******************* )344 environment departments of the continental U.S. Parts of the mid-Atlantic and the upper Midwest were ” record-breaking” damp. By the method, I presume somebody in Washington State is believing” however where I live has actually been drier than typical. “Based upon the information, that declaration holds true however states absolutely nothing about the remainder of the U.S. or environment modification, however I digress.(******************** )Jason Samenow composed an exceptional commentary in the Washington Post Capital Weather Condition Gang on” why” that area has actually been so damp. I will summarize his secret “meteorological points “:
- A consistent high pressure system has actually funneled wetness from the Atlantic Ocean and Gulf of Mexico into much of the eastern U.S.
- A 2nd location of high pressure near Alaska affected the jet stream pattern.
- The jet stream, which highly governs where mid-latitude systems and fronts, has actually intended storm tracks right into the Upper Midwest and Mid-Atlantic.
Other elements consist of Cyclone Florence and the weak El Nino that just recently started, however much of the record-breaking duration was connected with El Nino neutral or really weak condition. In reality, the NOAA NCEI synoptic summary for January 2019 specified, “The Earth’s ocean-atmosphere system continued in an ENSO-neutral state throughout January 2019 …” I am on the fence on the El Nino connection, however specialists like SUNY-Albany climatic researcher Paul Roundy argue that there might be more of signal than we believe. As Samenow pointed, “opportunity” and weather pattern irregularity definitely might describe the last 12 months. Nevertheless, it is careless to overlook environment modification since occasions follow the anticipated physics.
Deke Arndt’s Tweet took advantage of something environment researcher anticipated lots of years earlier, a speeding up water cycle. NASA’s Earth Observatory supplies a clear summary of what a faster water cycle indicates:
as the lower environment ends up being warmer, evaporation rates will increase, leading to a boost in the quantity of wetness distributing throughout the troposphere (lower environment). An observed effect of greater water vapor concentrations is the increased frequency of extreme rainfall occasions, generally over acreage.
Is this taking place? The
response is yes.
The2018 U.S. National Environment Evaluation report reveals that the heaviest rainfall occasions have actually ended up being more extreme given that the late1950 s( graphic above). Environment designs likewise recommend that this pattern will continue. (******************************* )A growing body of research study continues to reveal that the warming Arctic impacts the jet stream through a procedure called Arctic Amplification. According to NOAA’s site:(**** )
Researchers have actually observed that the minimized temperature level distinction in between the North Pole and tropics is connected with slower west-to-east jet stream motion and a higher north-south dip in its course. This pattern triggers storms to stall and magnify, instead of move away as they typically utilized to do. At midlatitudes, more severe weather condition arises from this brand-new pattern, consisting of dry spells, floods, colds spells, and heat waves.(**** )